Hitchhiker Stickymoss
Millions of years ago, some stickymoss had been swept by westward ocean currents from their home in Wright to the eastern shores of Glicker and Barlowe. There, they grew into a new population of stickymoss, finding much the same crystal flora hosts as they had in their place of origin. However, following their instincts to find chitinous trunks and climb them, they often accidentally found themselves climbing up onto the chitinous legs of arthrotheres instead. One offshoot evolved to specailize in sticking to those instead of to flora. These became hitchhiker stickymoss.
Hitchhiker stickymoss is physically much the same as its ancestor, but its behavior and lifestyle have shifted. Their juveniles still crawl around in the water, much like juveniles have done all the way back to wormstems, but they now inhabit freshwater instead of saltwater. Although they can breathe air through their spiracles, their spiracles must stay moist at all times, and they must consume lots of water to produce their mucus, so the juveniles never venture far from the water. Once they near adulthood, however, and a terrestrial arthrothere comes to the water to drink, bathe, or ford it, the hitchchiker stickymoss will climb up it and stick to it. This has provided a useful advantage in dispersal, allowing them to cross all across the tropical wet zones of Barlowe and Glicker. They cannot handle areas that are drier than monsoon forest, however, as their mucus would dry out.
Hitchhiker stickymoss retains more of its juvenile characteristics into adulthood than is typical of its relatives. They keep most of their musculature and a rudimentary nervous system, and they never lose their eyes. While stuck to a host, they are effectively dormant, behaving more like flora than fauna. However, they are capable of reverting to a juvenile-like state in which they can move again. It is therefore most accurate to consider them as having a floral and a faunal state, with the ability to switch between the two depending on circumstances. They return to a faunal state when their host dies, or when they are ready to breed and come across a body of freshwater. They will then crawl into the water and spawn. Like before, immature juveniles are strictly male, while adults are hermaphroditic. After spawning, they'll wait for another host to come by, allowing them to return to their floral state and be transported to yet another location.